1. Field of the Invention
The present invention relates to an internal cleaning apparatus for cleaning an interior of an object to be cleaned, such as a tank or a stack, which has an internal space.
2. Description of the Related Art
As a related art of this kind of internal cleaning apparatus, an internal cleaning apparatus has been widely known wherein a cleaning nozzle is affixed to a revolving rotary shaft configured to be revolvable about a cleaning supply pipe and axially rotatable, wherein the nozzle portion is inserted in an internal space of an object to be cleaned, and a cleaning is carried out as a cleaning liquid is three-dimensionally sprayed by causing the nozzle to revolve around the cleaning liquid supply pipe while revolving about the revolving rotary shaft (JP-UM-B-63-2145 and JP-B-6-94128). Also, a cleaning apparatus, whose cleaning action has been enhanced by using a gas-liquid mixture flow ejected by mixing a liquid and a gas, has also been developed (JP-A-2004-223409).